Umbrella stand



FIG. 1 is a perspective view of an umbrella stand showing my new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a back view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The ornamental design for an umbrella stand, as shown.